Electronic and Structural Modification of Three-Dimensional Porous NiCo@NF as a Robust Electrocatalyst for CO₂ Emission-Free Methanol Upgradation to Boost Hydrogen Co-production

Abstract

Electrochemical hydrogen evolution reaction (HER) coupled with methanol oxidation reaction (MOR) is an innovative process to attain energy-efficient hydrogen generation with more valuable formate product co-generation. Herein, we present 3D porous bimetallic NiCo nanostructures with oxygen vacancies grown on a nickel foam surface (Ov-NiCo@NF) as efficient electrocatalysts that show integrated highly selective methanol oxidation along with hydrogen evolution. The electronic structure of Ov-NiCo@NF is tuned by surface oxygen vacancies that provide a high active surface area and optimum chemisorption energy for selective methanol upgradation to formate. The metallic porous nanostructures and interconnected dendritic growth of nanoparticles ensure electrolyte penetration, with faster gas release ability, that enhances charge transfer kinetics and suppresses support passivation during MOR and HER. The 3D porous Ov-NiCo@NF exhibits improved methanol conversion activity, requiring 1.30 and 1.42 V (vs RHE) to achieve 50 and 100 mA cm–2 current densities for MOR, respectively. Furthermore, an integrated two electrode setup (Ov-NiCo@NF//Ov-NiCo@NF) requires a cell voltage of 1.41 V to attain 25 mA cm–2 current density for methanol-upgrading-assisted water electrolysis, while a higher cell voltage (1.62 V) is required in the electrolyte without methanol (overall water splitting).

Review and Perspective of Nickel and Its Derived Catalysts for Different Electrochemical Synthesis Reactions in Alkaline Media for Hydrogen Production

“…The catalyst exhibited 340.5 mA/cm 2 current density at 1 V with excellent durability (93% retention of current density after 2 h) in 1.0 M KOH in the presence of 1.0 M CH 3 OH. Arshad et al 99 also prepared a porous NiCO@NF electrocatalyst with structural and electronic modulation for CO 2 emission-free methanol oxidation to enhance H 2 coproduction. Their integrated two-electrode setup (O v -NiCo@NF//O v -NiCo@ NF) reached a 25 mA/cm 2 current density at a cell potential of 1.41 V during methanol oxidation-assisted water electrolysis, while a larger cell potential of 1.62 V is needed for overall water splitting (without methanol).…”